It is linked to better blood glucose control, which is important because uncontrolled blood sugar is what causes symptoms of diabetes and increases your risk for complications.[1]

If you do not already know, ask your healthcare provider for guidelines on when you should check your blood sugar. You should also find out what the normal peaks and troughs are at different times of the day so you know which fluctuations are normal and which may require action at home or a call to your provider for medical advice or care.

When to Check Blood Sugar

Your doctor should let you know when to check blood sugar. The National Institutes of Health (NIH) states that when you should check depends on which medications you take and which type of diabetes you have.[2] People on insulin tend to need to check blood glucose more often. People who manage diabetes with diet and exercise may check their blood sugar less frequently.

The most common times to check include:

First thing in the morning, before you have eaten anything.

Before lunch, dinner, and snacks.

Before bedtime.

Before and after exercising.

Whenever you have symptoms of hypoglycemia or hyperglycemia or suspect that you have out-of-range levels.

When something is out of the ordinary, such as when you are ill or you are changing the type, dose, or timing of diabetes or other medications.[3]

There are normal peaks and troughs to blood glucose levels. The target blood sugar levels when testing at home depend on factors such as the time of day, when you last ate, and whether you have exercised within the past several hours. Goals for blood sugar also depend on personal factors such as your age, how long you have had diabetes, and your typical blood sugar control.

This blood sugar chart can give you an idea of standard goal ranges for blood sugar testing.

Normal Peaks and Troughs in Blood Sugar

We hear a lot about keeping blood sugar levels stable, but that is not realistic or even desirable. An example of why you might want a sudden increase in blood glucose is during the stress response, also known as “flight or fight.” That is the response that happens when you are facing a challenge and feel a surge in energy. Your body is preparing to respond, and that energy comes from higher blood sugar.

In contrast, a time when blood sugar should drop is at night when you are not using much energy. Your muscles are not demanding it, so there is no need to have a lot of sugar sitting in your blood.

Insulin is not the only hormone that control blood sugar levels. These peaks and troughs are also controlled by many other hormones. Glucagon and cortisol are examples of just two of the other hormones that affect blood glucose levels (they happen raise blood sugar) and vary with time of day and whether you have eaten recently.

It makes sense to see normal peaks and troughs when you consider the effects of so many factors, from insulin and other hormones, to your mood and stress levels, to your recent food and exercise.

That said, excessive fluctuations are not normal. They can be your body’s signal to you that you can improve your blood sugar control. The two ends of the scale that both signal a problem are:

Hyperglycemia, or high blood sugar.

Hypoglycemia, or low blood sugar.

Depending on how extreme the readings are and what you think may have caused them, you may need to do anything from simply taking note of them to treating them yourself to checking with your healthcare provider.

Hyperglycemia

Hyperglycemia, or high blood sugar, is the hallmark of diabetes. Having chronic high blood sugar raises your risk for complications. Acute hyperglycemia, or high blood sugar over a few hours or days, can also be dangerous. It can result from many factors.

Emotional or physical stress, including being sick with a cold or other illness.

Weight gain.

Eating too much sugar or starch, or too many fried foods, processed meats, and other poor choices.

Skipping insulin or other diabetes medications or taking medications such as steroids that interfere with blood sugar control.

Physical inactivity.

You may not have symptoms until your blood sugar gets over 180 to 200 mg/dl.[4] At that point, you might detect classic symptoms of diabetes such as increased thirst and urination, blurry vision, a headache, and lethargy. Without treatment, you could develop an emergency situation called diabetic ketoacidosis. You could have nausea, vomiting, and stomach pain, and confusion, and even go into a coma.

Treatment for hyperglycemia depends on how severe it is, what you think the cause may be, and the plan that you and your doctor have made.

Take your medications if you forgot a dose and your doctor recommends it.

Drink water or other calorie-free fluids to dilute the sugar in your blood.

Exercise if it is safe so that you can increase insulin sensitivity.

Contact your doctor if symptoms do not go away or if your blood sugar does not return to normal, or if your blood sugar goes over 240 mg/dl.

Hypoglycemia

Diabetes may be defined by high blood sugar levels, but diabetics also need to contend with low blood sugar, or hypoglycemia. It seems ironic, but hypoglycemic episodes are more frequent when your glucose control is less tight. That is, frequent hypoglycemia may be a clue that your next diabetic A1C test could be a little higher.

Your blood sugar levels can fall for many reasons.

Drinking alcoholic beverages, especially in excess or on an empty stomach.

Physical activity, especially when unplanned or more intense than usual.[5]

Delaying or skipping a meal or snack.

Taking a medication that interferes with blood sugar regulation.

You have level 1 hypoglycemia if your blood sugar is 54 to 70 mg/dl. Level 2 hypoglycemia occurs if your levels drop below 54 mg/dl. Hypoglycemia symptoms can include hunger, confusion, weakness, racing heart, and irritability. If you do not treat mild hypoglycemia promptly, you risk a progression to level 2 hypoglycemia and potentially an emergency situation such as seizures, coma, or loss of consciousness.

Mayo Clinic recommends eating fast-acting carbs if you think you have hypoglycemia but are unable to check your blood sugar immediately.[7]

Fasting-acting carbs are sugary foods. Good choices include 4 glucose tablets that you can get at a pharmacy, 1 tablespoon of honey or jelly, 3 or 4 pieces of hard candy, or 4 to 6 oz. of fruit juice. You should always carry a sugary food with you. Fat slows absorption, so chocolate and pastries are poor choices.

You may too confused or weak to take care of yourself if you have level 2 hypoglycemia. You may even be unconscious. You can plan ahead to stay safe.

Wear a bracelet that identifies you as diabetic.

Get a prescription for glucagon and let people around you know how to use it.

Improving Blood Sugar Control

Do not get discouraged if you have some or many out-of-range values. It can take a while to figure out what works best for your blood glucose and how to make diabetes management part of your regular routine. There is a good chance that one or more of the following can improve your values.

Lark Diabetes Care can help you incorporate those healthy behaviors into your life. It is smartphone app-based health coach that works on all of those behaviors and more with you in a customized program that includes encouragement, education, reminders, tracking, and goal-setting.

It also comes with an easy-to-use glucometer that automatically syncs with the app. Each time you take a blood glucose reading, your numbers appear in the app and you get instant feedback and coaching so you can learn and be motivated. It also provides summaries on your recent trends, and stores your data so you can talk about it with your doctor at your next appointment.

Lark Diabetes Care may be offered through your healthcare provider, so there’s no reason not to get on top of your blood sugar level schedule today!